An increase in the supply of new housing is fundamental to resolving the current crisis; one of the main aims of HTB is to help encourage the building of additional new properties. By restricting HTB solely to new dwellings and new self builds, the resulting increase in demand for affordable new build homes encourages the construction of an additional supply of such properties. If the HTB were also available for second-hand properties, it would limit the incentive effect on the provision of additional supply.
I have no plans to extend the Help to Buy incentive (HTB) to second-hand properties.